Re: [PATCH] X86: Disassemble primary opcode map's group 2 ModRM.reg == 6 aliases correctly

[Borislav Petkov <bp at suse dot de>]

On Tue, May 30, 2017 at 07:53:22AM -0700, H.J. Lu wrote:
> II meant "the same instruction with different opcodes".

Well, Jan's suggestion to use SAL makes more sense to me because we're
dumping the ModRM.reg == 6 variant here. And this is the *correct*
instruction name, see http://sandpile.org/x86/opc_grp.htm, for example.

In group 2 you have, in that order:

ROL, ROR, RCL, RCR, SHL, SHR, SAL, SAR

and SAL is the 7th (ModRM.reg = 110b) and we're stating exactly that:
this is the 7th instruction in the tables.

Mind you, no tool will ever generate this instruction so I don't think
anyone would *actually* see it (or get confused by it) - this is simply
closing the gap in objdump decoding there, nothing more. We're not
changing the assembler, as you requested. No one would go and write sal
all of a sudden.

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    Boris.

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